• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.1
• /
• pp.53-58
• /
• 2013

In this paper, we present a framework for collision avoidance of UGVs by vision-based control. On the image plane which is created by perspective camera rigidly attached to UAV hovering stationarily, image features of UGVs are to be controlled by our control framework so that they proceed to desired locations while avoiding collision. UGVs are assumed as unicycle wheeled mobile robots with nonholonomic constraint and they follow the image feature's movement on the ground plane with low-level controller. We used potential function method to guarantee collision prevention, and showed its stability. Simulation results are presented to validate capability and stability of the proposed framework.

• Bulletin of the Korean Chemical Society
• /
• v.21 no.1
• /
• pp.69-74
• /
• 2000

Applicability of Thermal field flow fractionation (ThFFF) was investigated for the analysis of masticated natural rubber (NR) adhesives produced bya hot melt mastication process. An optimum ThFFF condition for NR analysis was found by using tetrahydrofuran (THF) as a solvent/carrier and a field-programming. Low flowrate (0.3 mL/min) was used to avoid stopping the flow for the sample relaxation. Measured molecular weight distribution was used to monitor degradation of rubber during the mastication process. Rubber samples collected at three different stages of the mastication process and were analyzed by ThFFF. It was found that in an anaerobic process rubber degradation occurs at the resin-mixing (compounding) zone as well as in the initial break-down zone, while in an aerobic process most of degradation occurs at the initial breakdown zone. It was also found that E-beam radiation on NR causes a slight increase in the NR molecular weight due to the formation of a branched structure.

• Computers and Concrete
• /
• v.16 no.4
• /
• pp.587-604
• /
• 2015

The hybrid-type penalty method (HPM) is suitable for representing failure phenomena occurring during the transition from continua to discontinua in materials such as concrete. Initiation and propagation of dominant cracks and branching of cracks can easily be modeled as a discrete crack. The HPM represents a discrete crack by eliminating the penalty that represents the separation of the elements at the intersection boundary. This treatment is easy because no change in the degrees of freedom for the discrete crack is necessary. In addition, it is important to evaluate the correct deformation of the continua before the crack formation is initiated. To achieve this, we implemented a constitutive model of concrete for the HPM. In this paper, we explain the implemented constitutive model and describe the simulation of an anchor bolt pullout test using the HPM demonstrating its capability for evaluating progressive failure.

• Nuclear Engineering and Technology
• /
• v.51 no.7
• /
• pp.1822-1827
• /
• 2019

Mechanical responses and failure behaviors of advanced C/C composite tube are very important for structural component design in nuclear reactor. In this study, an experimental investigation was conducted to study mechanical properties of C/C composite tube. Quasi-static compression loading was applied to a type of advanced composite tube to determine the response of the quasi-static load displacement curve during progressive damage. Acoustic emissions (AE) signals were captured and analyzed to characterize the crack formation and crack development. In addition, the crack propagation of the specimens was monitored by imaging technique and failure mode of the specimen was analyzed. FEM is appled to simulate the stress distribution. Results show that advanced C/C composite tube exhibits considerable energy absorption capability and stability in load-carrying capacity.

• Bulletin of the Korean Chemical Society
• /
• v.7 no.4
• /
• pp.279-282
• /
• 1986

The MNDO calculations were performed in order to investigate the gas-phase reaction mechanism of 2-propene-1-al oxide, as a model compound of dypnone oxide(1,3-diphenyl-2-butene-1-one oxide) with the chloride ion. Optimized geometries and heats of formation for two probable concerted pathways, CHO and H migration, were determined and their activation energies were obtained. MO results show that although the formyl migration is thermodynamically more favorable than the hydride migration, the latter kinetically predominates over the formyl migration, which is contrary to the established migrating preferences. It is concluded that the hydride migratory propensity is catalyzed by the chloride ion by reducing the capability of the carbonyl ${\pi}$ bond to participate in the migration.

• SUVANNABHUMI
• /
• v.10 no.1
• /
• pp.117-147
• /
• 2018

Only a few researchers highlighted the implementation of Indonesian Sustainable Palm Oil (ISPO) certification. These neglected the importance of analyzing the different trajectories of the relations of production in Indonesian palm oil development. As a result, there is a prevailing doubtful attitude on ISPO legitimation. This paper aims to identify how independent smallholder pilot projects give meaning to ISPO legitimation and implementation. It explores production relations in a smallholder community, focusing on land ownership, the formation of a cooperative, and response capability in cases of failure. This paper reveals that the project brought greater understanding to the community with regards to sustainability, as well as strengthened cooperation between the company and the cooperative. This, despite the community's confronting the same problems of land legality as other independent farmers, as the community is located inside the company concession (Hak Guna Usaha, HGU).

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.229-229
• /
• 2010

With the scaling down of ultra large integrated circuits (ULSI) to the sub-50 nm technology node, the need for an ultra-thin, continuous and conformal diffusion barrier and Cu seed layer is increasing. However, diffusion barrier and Cu seed layer formation with a physical vapor deposition (PVD) method has become difficult as the technology node is reduced to 30 nm and beyond. Recent work on self-forming barrier processes using PVD Cu alloys have attracted great attention due to the capability of conformal ultra-thin barrier formation using a simple technique. However, as in the case of the conventional barrier and Cu seed layer, PVD of the Cu alloy seed layer will eventually encounter the difficulty in conformal deposition in narrow line trenches and via holes. Atomic layer deposition (ALD) has been known for its good step coverage and precise thickness control, and is a candidate technique for the formation of a thin conformal barrier layer and Cu seed layer. Conformal Cu-Mn seed layers were deposited by plasma enhanced atomic layer deposition (PEALD) at low temperature ($120^{\circ}C$), and the Mn content in the Cu-Mn alloys were controlled form 0 to approximately 10 atomic percent with various Mn precursor feeding times. Resistivity of the Cu-Mn alloy films decreased by annealing due to out-diffusion of Mn atoms. Out-diffused Mn atoms were segregated to the surface of the film and interface between a Cu-Mn alloy and $SiO_2$, resulting in self-formed $MnO_x$ and $MnSi_xO_y$, respectively. No inter-diffusion was observed between Cu and $SiO_2$ after annealing at $500^{\circ}C$ for 12 h, indicating an excellent diffusion barrier property of the $MnSi_xO_y$. The adhesion between Cu and $SiO_2$ was enhanced by the formation of $MnSi_xO_y$. Continuous and conductive Cu-Mn seed layers were deposited with PEALD into 32 nm $SiO_2$ trench, enabling a low temperature process, and the trench was perfectly filled using electrochemical plating (ECD) under conventional conditions. Thus, it is the resultant self-forming barrier process with PEALD Cu-Mn alloy film as a seed layer for plating Cu that has further potential to meet the requirement of the smaller than 30 nm node.

• IE interfaces
• /
• v.25 no.1
• /
• pp.52-63
• /
• 2012

Up-to-date enlargement of the scale of global outsourcing has brought about the need of systematic and efficient tools for competitive supplier discovery located in various areas. A web-based business supporting system, referred to as Excellent Manufacturer Scouting System(EMSS), is being developed to serve core business functions including supplier discovery, negotiation, and collaboration between overseas buyers and domestic suppliers throughout the process of supply chain formation. In this paper, a supplier assessment model devoted to evaluation of core manufacturing capability is proposed by targeting small and medium sized mold companies. The assessment model will eventually be loaded to EMSS. Even if many well-designed models for supplier assessment have been presented in literature, most of them limit the evaluation criteria to somewhat general information on a given supplier, such as cost, delivery time, quality, rather than core manufacturing capability itself. This research is pioneering work on supplier assessment from the viewpoint of manufacturability. The proposed assessment model classifies assessment indices into six criteria, which have been drawn by intensive survey and analysis of the mold industry. Actual assessment indices for each criterion are also presented along with an exemplary evaluation result.

• Journal of the Microelectronics and Packaging Society
• /
• v.12 no.1 s.34
• /
• pp.9-16
• /
• 2005

This paper presents the development of new anisotropic conductive adhesives with enhanced thermal conductivity for the wide use of adhesive flip chip technology with improved reliability under high current density condition. The continuing downscaling of structural profiles and increase in inter-connection density in flip chip packaging using ACAs has given rise to reliability problem under high current density. In detail, as the bump size is reduced, the current density through bump is also increased. This increased current density also causes new failure mechanism such as interface degradation due to inter-metallic compound formation and adhesive swelling due to high current stressing, especially in high current density interconnection, in which high junction temperature enhances such failure mechanism. Therefore, it is necessary for the ACA to become thermal transfer medium to improve the lifetime of ACA flip chip joint under high current stressing condition. We developed thermally conductive ACA of 0.63 W/m$\cdot$K thermal conductivity using the formulation incorporating $5 {\mu}m$ Ni and $0.2{\mu}m$ SiC-filled epoxy-bated binder system to achieve acceptable viscosity, curing property, and other thermo-mechanical properties such as low CTE and high modulus. The current carrying capability of ACA flip chip joints was improved up to 6.7 A by use of thermally conductive ACA compared to conventional ACA. Electrical reliability of thermally conductive ACA flip chip joint under current stressing condition was also improved showing stable electrical conductivity of flip chip joints. The high current carrying capability and improved electrical reliability of thermally conductive ACA flip chip joint under current stressing test is mainly due to the effective heat dissipation by thermally conductive adhesive around Au stud bumps/ACA/PCB pads structure.

• Journal of Korean Society for Quality Management
• /
• v.48 no.1
• /
• pp.125-147
• /
• 2020

Purpose: This study would measure the users'perceived overall quality level of A automobile Company, which has leading market power in the domestic automobile market and analyze the causal relationships in the quality value process Model to quality capability, customer value and loyalty based on that. Especially, this study would analyze the relative impacts of the users'perceived risks appearing in the quality value process model of the formation of Quality Factors(QF), Customer Value(CV), and Customer Loyalty(CL) and analyze the moderating effect of the causal relationships among the components. Methods: For an analysis of causal relationships connected to QF, CV, and CL of the customers who purchased Auto manufacturer A's automobile users, 179 users who used within 3 years were utilized as samples for the analysis. As for QF, based on the Garvin(1988), the QF of automobiles were redesigned. For a structural equation analysis of the entire research model, the PLS(S(Partial Least Square) model was utilized. Results: As a result of an analysis, R2 of CV and CL was 0.652 for CV and 0.664 for CL, which was a very stable Goodness of fit. As a result of an analysis of the hypotheses of QF and CV, automobile performance, conformance, aesthetics, serviceability, and durability. In addition, it turned out that the perceived risk had a moderating effect on convenience, service availability, and perceived quality. Conclusion: This study found that the perceived quality risk appearing among automobile users had negative effects on the quality value process model to QF, CV and CL. In contrast, there were factors not affecting the users'quality value process in spite of the perceived risk. These factors can suggest important managerial implications in that they can be utilized as Auto manufacturer A's market-dominant strengths.